It's an interesting article in that it analyzes the outcomes. Not sure what to make of it though. It kind of says that:
Some players are great from day 1 (Grant Hill, Lebron James, Paul Pierce, Kevin Durant, Carmelo, Vince Carter)
Some players take a while to develop into greatness (Kobe Bryant, Leonard, the greek freak, Derozan, Paul George, Rashard Lewis, Anthony Davis, Joe Johnson, KP, Michael Redd, allan houston)
Some players start out looking like future stars but failed to rise, evolving into either into role players or out of the league (Landry Fields, Marshon Brooks, Kerry Kittles, Shane Battier, Lamar Odom, Tim Thomas)
I reckon you're good from the get go, or you're young.
Not sure if I missed it, but there doesn't seem to be a good predictor. But that younger players seem to have a longer leash. (which probably makes sense, since conventional wisdom says if you show skills/talent early, you have greater upside...)
I would find it curious if any players who didn't put up appreciable numbers over their first 3 seasons still emerged as NBA starters (let alone All-stars).